Users often find it difficult to identify the obscured words that a normal CAPTCHA uses for form submissions. Dice CAPCHA is a new way to reduce this difficulty, while still helping to prevent spam.
It works by asking the user to calculate a simple sum using the numbers displayed on a number of dice.
It is easy to use and can be added to an existing form in just a few lines of code. The CAPTCHA is a single simple image and will work in any browser.
The background colour and colour of the + and = signs are fully customisable using hex colour values. There are three colours for dice; red, green and blue. You can also have two different dice colours on the same CAPTCHA or have them chosen at random.
See: http://codecanyon.steve-j.co.uk/dice-captcha/ for full details and examples.